Scrollbar and right window border

When a scrollbar is on display in APP or TOD windows, the right
vertical border (outside the scrollbar) is not highlighted
when the window is selected.

The scrollbar itself is always highlighted:
- when APP or TOD is deselected
- in configuration windows where borders otherwise are not

The patch moves the scrollbar parameters from arguments of
draw_scrollbar() to the function itself.

The highlight argument to draw_scrollbar() was always 1.
Instead call circumstances are figured out and highlight set
accordingly.

Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>

src/calcurse.h

@@ -1144,7 +1144,7 @@ long date_sec_change(long, int, int);
 long update_time_in_date(long, unsigned, unsigned);
 time_t get_sec_date(struct date);
 long min2sec(unsigned);
-void draw_scrollbar(WINDOW *, int, int, int, int, int, unsigned);
+void draw_scrollbar(struct scrollwin *);
 void item_in_popup(const char *, const char *, const char *, const char *);
 time_t get_today(void);
 long now(void);